1. Field of the Invention
The invention relates to a laser robot for workpiece machining, comprising a first robot link on whose longitudinal axis a first beam path of a first laser beam is to be arranged, which first beam path can be deflected at a side facing the workpiece into an axis-parallel second beam path, and in which a third beam path of a second laser beam is to be arranged axis-parallel to the first beam path of the first laser beam, and comprising focusing optics arranged in a robot hand downstream of the first robot link from where the laser beams reach the workpiece.
2. Description of the Related Art
A laser robot with the aforementioned features is known from EP-A-0 901 875. The first working laser beam of the known robot is guided to an attachment unit which has the task of deflecting the first laser beam from the first beam path into the second beam path which is axis-parallel to the first beam path. In the known laser robot a third beam path of a second working laser beam can be provided, in particular, such that it is to be arranged parallel to the first beam path of the first working laser beam. However, this is possible only when the attachment unit for deflection of the first working laser beam is removed. This is so because the attachment unit projects into the second and also into the third beam path since these two aforementioned beam paths are aligned with one another. Accordingly, when different types of working laser radiation are to be employed, for example, a CO2 laser radiation or a diode laser radiation, a retrofitting of the robot link must be carried out during which the attachment unit is to be either mounted or demounted. This is complex and requires a subsequent adjustment. Moreover, it is not possible to operate the robot simultaneously with two laser beams.
It is an object of the present invention to further develop a laser robot having the aforementioned features such that the workpiece machining performed with it can be carried out without retrofitting, in particular, when it is to be used for the simultaneous machining with two laser beams.
In accordance with the present invention, this is achieved in that in one of the beam paths of the first laser beam an optical beam combination device of both simultaneously active laser beams is arranged from where both laser beams reach simultaneously axis-parallel or with coinciding axes the focusing optics in the robot hand and in that both laser beams reach the workpiece simultaneously axis-parallel, with coinciding axes, or via an optical beam splitting device which splits laser beams with coinciding axes into axis-parallel laser beams.
It is important in regard to the invention that the workpiece machining action by means of the laser robot can be carried out with simultaneous use of two laser beams. Both laser beams are guided within the interior of the robot and within, in particular, the interior of a robot link as well as a downstream robot hand so that the robot does not require external attachment units and external articulations particularly in the area of the robot hand which otherwise would impede the freedom of movement and the application range of the robot. In this respect, it is advantageous to combine the laser beams in a robot link and to convey them axis-parallel or with coinciding axes into the robot hand, in particular, into the focusing optics. From here, it is then possible to enable the desired application of the laser beams on the workpiece (tool) in that the laser beams are used simultaneously axis-parallel, with coinciding axes, or separate from one another, wherein, if needed, a beam splitting device is employed. By means of the laser robot, it is possible to perform most different machining and measuring tasks, also in combination. It is not required to retrofit the robot in order to be able to work with the two laser beams simultaneously or successively in one working step. Also, the coupling of the lasers to the robot must not be changed.
The laser robot has a particularly advantageous configuration when the second beam path and a fourth beam path, starting at the exit of the beam combination optics and common to both laser beams, are arranged at a certain spacing from the first beam path within a plane defined by the longitudinal axis of the robot link and a pivot axis perpendicular thereto of an additional robot link of the robot hand. As a result of the spacing of the common beam path from the longitudinal axis of the robot link, it is possible to configure the additional robot link in a space-saving way and advantageously such that, primarily with respect to the focusing optics, the common beam path is arranged as much as possible peripherally and the central space is therefore available for inserts, for example, for focusing optics and/or an additional link.
In a further embodiment of the described configuration, it can be advantageous to configure the laser robot such that the additional robot link has a mirror whose axis coincides with the pivot axis of the robot link and with which the two laser beams can be simultaneously guided to the focusing optics which is arranged downstream of the beam splitting device.
The laser robot and, in particular, a robot hand arranged downstream of the first robot link can be expediently configured such that the focusing optics, arranged axially coinciding with the longitudinal axis of the first robot link, is arranged in the additional robot link or in a rotational axis of the additional robot link.
It is preferred to configure the laser robot such that the optical beam splitting device has a splitting element which can be penetrated by the laser radiation of one of the laser beams and which reflects the laser radiation of the other laser beam. For example, by means of the splitting element, the different reflection behavior of certain materials in regard to laser beams of different wavelengths can be taken advantage of. While one laser radiation has a wavelength which passes through the splitting element, i.e., is not reflected, the other laser radiation is reflected because the splitting element is not transmissive for this wavelength.
It is advantageous when the splitting element is a splitting plate which is arranged at an angle to the laser beams. It can be manufactured easily, and products available on the market can be used at least as a starting material for the plates to be employed.
In order to be able to advantageously employ the beam splitting for conventional machining actions, the laser robot is configured such that a deflection plate is optically arranged downstream of the splitting element from where a split laser beam can be guided to the workpiece. The deflection plate can be arranged, for example, such that both laser beams act spaced apart and parallel on the workpiece.
In order to improve the range of application of the laser robot in the afore described sense, it is configured such that the deflection plate has an adjustable spacing relative to the splitting element and/or that the splitting element together with the deflection plate can be rotated about an axis of rotation determined by the focusing optics optically arranged upstream. An adjustment of the spacing between the deflection plate and the splitting element and a common rotation of the splitting element and of the deflection plate can be employed individually and in combination with one another for the purpose of adjusting the laser robot to the task on hand, respectively.
One possible configuration of the laser robot resides in that the optical beam splitting device is arranged optically upstream of the focusing optics which has a focusing lens for one of the beams and a focusing mirror for the other. As a result of this, the focusing of the laser beams can be realized differently in that the focusing lens, on the one hand, and the focusing mirror, on the other hand, are sized differently.
The above described laser robot can be configured such that the focusing mirror is at the same time a deflection part of the beam splitting device. This results in a corresponding simplification of the configuration of the robot. Such a simplification is particularly important when the beam splitting device is arranged in the vicinity of the beam exit of the robot hand because it is desired to provide in this area the most narrow configuration of all components in order to limit the spatial range of use of the robot as little as possible.
The laser robot can be configured such that both laser beams are working laser beams with different radiation parameters. With two working laser beams that are simultaneously active or are cycled in one working step different machining actions can be for performed, for example, a welding process and a cutting process.
The invention relates also to a method for workpiece machining by means of a laser robot, wherein the robot is provided in a first robot link with a first beam path of a first working laser beam of first radiation parameters, and with which a second working laser beam of second radiation parameters, which is axis-parallel to the first beam path, can be employed.
In order to improve this method in the sense of the above-mentioned object, it is performed such that both working laser beams in the robot link are combined axis-parallel or with coinciding axes on a common beam path, and that the combined working laser beams can simultaneously machine in one working step the workpiece at the same machining location or at different, spaced apart machining locations by employing the different radiation parameters. It is of special importance in connection with the method that a broad machining spectrum results because of the simultaneous use of two working laser beams of different radiation parameters. In this connection, the working laser beams can be employed at the same machining location or different, spaced apart machining locations. Different machining geometries and/or different material combinations can be machined in an optimal way. The machining can be carried out at optimized speed.
For certain machining tasks, it is expedient to focus the two working laser beams together. This holds true when the focus of both working laser beams can be identical because the same machining location is to be machined or when different machining locations which, however, have the same spacing relative to the focusing optics, are to be machined.
Preferably, it is possible to operate such that the two working laser beams are split apart in a robot hand arranged downstream of the first robot link. As a result of this, the common beam guidance, which requires only a minimal common cross-section, can be maintained into the robot hand and thus up to the location from where the working laser beams are then emitted onto the workpiece.
A further method is possible in that the spacing of the two working laser beams which are separated from one another can be adjusted corresponding to the required spacing of the machining locations, respectively. When the spacing of the working laser beams is identical to the spacing of the machining locations, a very simple adjustability of the spacing of the machining locations is apparent, in particular, for working laser beams that are parallel to one another, by means of the components of the laser robot which affect the spacing of the working laser beams relative to one another.
When the working laser beams are used with laser radiation of different wavelengths, particularly the beam combination and beam splitting devices can be realized with simple components which have proven successful for the respective wavelengths. Furthermore, each working laser beam can be employed for a special machining process which deviates from the machining process of the other working laser beam, respectively, in correlation with the employed wavelengths, respectively.
For example, it is possible to weld as well as cut temporarily when a working laser beam of a Nd:YAG laser and, at a spacing thereto, at the same time a working laser beam of a CO2 laser are used.
For special machining tasks, a method is suitable in which two working laser beams operate with laser radiation of different wavelength on the same machining location in one working step to perform cutting and welding successively and/or intermeshingly.